Press for bending wood.



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No. 679,287.. Patented july 30, |90i.

F. H. ANcnurr.

PRESSFOR BENDING WOOD.

(pplication filed Apr. 25; 1900.),

FRANK H. BANOROFT, OF GARDNER, MASSACHUSETTS, ASSIGNOR OF ONE- HALF TO HENRY M. RIOH, OF SAME PLAGE.

PRESS IFOR BENDING WOO.

SPECIFICATION forming part of Letters Patent No. 679,287, dated July 30, 1901.

Application iled April 25, 1900.

To all whom t may concern.-

Be it known that I, FRANK I-l. BANCROFT, a citizen of the United States, and a resident of Gardner,in the county of Worcester and Oommonwealth of Massachusetts, have invented certain new and useful Improvements in Presses for Bending Wood, of which the following is a specification, reference being had to the accompanying drawings, forming a part 1o of the same, in which- Figure 1 represents a front view of a press for bending wood embodying my invention. Fig. 2 is a side elevation of the same. Fig. 3 is a view of one end ofthe barP and a portion of one of the rack-bars. Fig. 4t is an end view, partly in section, of the forms N and X.

Similar reference-letters refer to similar parts in the dierent views.

My invention relates to a press for bending zo wood, having fixed and reciprocating bars whose opposing surfaces are curved or so shaped as to bend pieces of wood placed between them; and it consists in certain iinprovements in the press for bending wood z5 forming the subject of my application for Letters Patent of the United States, Serial No.

735,452, filed November l, 1899.

My invention has for its object to provide means for supporting the convex side of the 3o wood during the process of bending in order to cause the bending` strain to be more uniformly distributed; and it consists in the novel features as hereinafter described, and set forth in the annexed claims.

Referring to the drawings, A denotes the base of the machine, supporting a hydraulic cylinder B, having a plunger C. Mounted upon the base A are a pair of upright posts D, connected together at their top by a cross- 4o head E, constituting the upper form and consisting of a hollow shell having its under side E' presenting a convex surface and adapted to cooperate with a hollow movable form F,

capable of vertically sliding upon the upright posts Dand having a corresponding concave upper surface F, the forms E and F constituting pressing members between which the articles to be bent are placed.

Below the form F is a similar form G, hav- 5o ing a concave surface G', adapted -to coperate with a convex surface F2 on the under Serial No. 14,249. (No model.)

side of the form F, the pressing-surfaces E and F and F2 and G being adapted to bend articles of wood-such, for example, as chairlegs--so their curvature will correspond with the curved pressing-surfaces, the pressing being accomplished by carrying the movable forms F and G upwardly by the action of the plunger O in the manner common in machines of this class and as set forth in my 6o application aforesaid, Serial No. 735,452. In order to cause the central portion of the articles H to be bent to closely hug against the convex surfaces against which they are 'pressed in the operation of bending by the 65 upward motion of the movable forms, I place beneath the articles H a curved spring-plate I, having its ends resting upon the concave surface of the movable form and its convex surface bearing against the articles I-I and 7o crowding them into close contact with the convex pressing-surface. In the accompany ing drawings the articles H between the forms E and F are represented as having been pressed into their proper curved shape and held by fastening the movable form F to the upright posts D by means of the set-screws J. The forms F and G are represented in the drawings as separated in position to receive the articles I-I to be bent, which are sup- 8o ported upon the brackets K, with their upper surfaces against the central. portion of the form F. Beneath the articles H, between the forms F and G, is placed a spring-plate I, consisting of a curved elastic sheet of metal,` with its ends resting upon the concave surface of the form G and with its central portion arranged to press against the under side of the articles H as the form G is raised. As the articles H are bent the elastic sheet of metal I is 9o crowded downward and curved in the opposite direction and pressed against the concave surface G in the same position as the spring-plate between the forms E and F. The pressure of the spring-plate I causes the articles to be bent to be held closely against the central portion of the convex surface of the form upon which they are bent and applies a pressure to the opposite side of the bent articles, thereby preventing the splintering of the Ioo wood on its convex side and causing the bend ing strain to be more equally distributed throughout the entire width of the pressingsurface. Below the form G is shown a curved form M, which bears against the under surface of the form G and is provided on its under surface with a convex surface M', fitting the concave surface N of the form N and constituting the pressing-surfaces, between which the articles O are bent. The articles O when placed between the forms are supported between ribs O2 upon a thin sheet-metal apron O, which rests upon the form N when in its lowest position. The concave surface N of the form N is provided at its central portion with a recess N3, in which is placed a bar P, normally lying in the recess N3 with its ends projecting over the vertical bars Q Q, which are capable of a vertical sliding motion and are provided with rack-teeth R, engaged by pinions (not shown) on the shafts S S.

The shafts S carry upon their ends handwheels T, by which the shafts S are rotated in order to raise and lower the bars Q Q. The bars Q Q are provided upon their upper ends with a tongue Q', adapted to engage a groove P in the under side of the bar P, so that when the rack-bars Q are raised the bar P will be lifted and carried against the under side of the apron O with sufficient pressure to hold the articles O firmly against the convex surface l and the hand-wheels T are locked in position by means of a cam U, provided with a lever-handle V, by which the rim of the hand-wheel is clamped between the cam U and the bearing-surface W. The form N is then moved up by the plunger C until the bar P is received into the recess N3 and the pieces O bent to conform to the curved surface of the forms M and N. The lower form X is likewise provided with a recess Y, and the rack-bars Q Q are lowered and a bar placed in the recess Y and raised to hold the articles while they are being bent between the forms Grand X. The bar P is preferably slightly curved and elastic, so that as it is raised by the engagement of its ends by the vertically-sliding racks Q Q its central section is first carried into contact with the articles with the apron O', and as pressure is applied to the ends of the bar it becomes straightened, causing the pressure exerted by the center of the bar to be fully equal to that exerted by its ends. The movable forms `slide loosely on the upright posts D and a ways in the form X and` N are larger in crosssection than the vertically-sliding racks in order to provide for their free movement. I employ the pressure-bar P between the lower forms or the forms below the form M, and above the form M, I employ spring-plates, such as I and L.

What Il claim as my invention, and desire to secure by Letters Patent, is-

1. The combination with a pair of pressing members, adapted to bend the articles pressed between them, of means for applying a pressure to the center of the articles to be bent and consisting of an elastic curved plate having its ends bearing against one of the pressing members and its convex side applied to hold the articles against the other pressing member, substantially as described.

2. The combination of a pair of forms provided with opposing convex and concave pressing-surfaces, of a curved elastic plate with its ends resting on the concave surface, of one of said forms and with its convex surface adapted to hold the articles to be pressed against the convex surface of the other form, substantially as described.

3. The combination of pressing members provided with corresponding convex and concave surfaces, of a bar extending across and between said pressing members, rack-bars sliding in vertical ways and engaging said pressing-bar to carry it into contact with the articles to be pressed and hold them in contact with one of the pressing members, substantially as described.

In testimony whereof I have signed my 

